In a known process of this type, to prepare the starting mash either a bacteria-containing vinegar obtained submersed and stored with the access of air to the still surface with an acid content of from 10 to 13 g of acetic acid/100 ml of vinegar and from 0.5 to 1.5% by volume of alcohol which is mixed with alcohol-containing mash with a content of 2 g of acetic acid/100 ml of mash and approximately from 10 to 14% by volume of alcohol is used, or bacteria-free vinegar with a content of approximately from 10 to 12 g of acetic acid/100 ml of vinegar and from 0.0 to 0.5% by volume of alcohol is mixed with alcohol-containing mash with a content of up to 2 g of acetic acid/100 ml of vinegar and approximately from 10 to 14% by volume of alcohol, so that the starting mash has a content of from 6 to 9 g of acetic acid/100 ml of mash and from 4 to 7% by volume of alcohol. In the following the alcohol concentration is always given in percent by volume and the acetic acid concentration in mixed percentages, i.e. in g/100 ml. The sum of these two values is referred to as the total concentration. The starting mash prepared with bacteria-free vinegar according to the second variant is seeded with a ventilated submersed fermentation substrate containing acetic acid bacteria. The addition of the seeding substrate is carried out in the ventilated starting mash, the ventilation thereof being continued without interruption. After reaching an alcohol concentration close to zero, part of the vinegar prepared is removed from the fermentation tank and replaced by fresh mash.
It was previously thought that an acetobacterial strain produced by adaptation over many years would retain its properties, i.e. compatibility of high total and acetic acid concentrations, only in a continuous submersed high-percentage fermentation with a total concentration above 10%, or if vinegar is discharged from a fermentation of this type before the end of fermentation with an acetic acid content of approximately from 10 to 13 g/100 ml and from 0.5 to 1.5% by volume of alcohol and this untreated vinegar is stored with access of air to the still surface.
As a result of the unfavorable conditions of existence for the acetobacteria during the storage periods of differing duration, such as for example high acetic acid concentrations, low residual alcohol content, minimal nutrient provision, and poor oxygen supply, the starting time of a fermenter using a so-called "seeding vinegar" stored in this way for the preparation of starting mash with an acetic acid content of from 6 to 9 g/100 ml and from 4 to 7% of alcohol usually amounts to between 7 and 14 days, the starting time amounting to up to 20 days with a high starting total concentration, e.g. of 13%, and a corresponding age of the seeding vinegar.
When using filtered, high-percentage vinegar and corresponding mash with an acetic acid content of up to 2 g/100 ml and approximately from 10 to 14% of alcohol for the preparation of starting mash with from 6 to 9 g of acetic acid/100 ml and from 4 to 7% of alcohol and seeding with from 2 to 5 l of substrate fermenting submersed per 10,000 l of starting mash, the starting time of the fermenter still amounts to from 5 to 10 days depending upon the level of the starting mash total concentration.